Yesterday the guy run a similar benchmark at 1080p with the GTX1080
You will see the 1700 @ 3.9 matching the 7700K @ 5ghz on all benchmarks across the board (some loses 2-3 fps, other wins 2-3fps). And if you see the Ryzen CPU you can run 2 games on it because half of it is idling.
Its a good point the ryzen is not even been fully utilised as the 7700 is all most at peak ...maybe the driver from M$ re the scheduler may resolve this will see